Cannabinoid type 1 receptor antagonism ameliorates harmaline-induced essential tremor in rat

Background and purpose Essential tremor (ET) is a neurological disorder with unknown etiology. Its symptoms include cerebellar motor disturbances, cognitive and personality changes, hearing and olfactory deficits. Excitotoxic cerebellar climbing fibre hyperactivity may underlie essential tremor and has been emulated in rodents by systemic harmaline administration. Cannabinoid receptor agonists can cause motor disturbances although there are also anecdotal reports of therapeutic benefits of cannabis in motor disorders. We set out to establish the effects of cannabinoid type 1 receptor agonism and antagonism in an established rodent model of ET using a battery of accepted behaviour assays in order to determine risk and therapeutic potential of endocannabinoid system modulation in ET. Experimental Approach The behavioural effects of systemic cannabinoid (CB) receptor agonist (0.1, 0.5 and 1 mg kg-1 WIN55, 212-2) and antagonist (1 mg kg-1 AM251 and 10 mg kg-1 rimonabant) treatment on harmaline-induced (30 mg kg-1) tremor in rats was assessed using tremor scoring, open field, rotarod, grip and gait tests. Key Results Overall, harmaline induced robust tremor that was typically worsened across the measured behavioural domains by CB type 1 (CB1) receptor agonism but ameliorated by cannabinoid type 1 receptor antagonism. Conclusions and Implications These results provide the first evidence of effects of endocannabinoid system modulation on motor function in the harmaline model of essential tremor and suggest that CB1 receptor manipulation warrants clinical investigation as a therapeutic approach to protection against behavioural disturbances associated with essential tremor

An evidence for lack of pseudoneglect in patients with schizophrenia:An ERP study

Studies have reported an altered expression of pseudoneglect in patients with schizophrenia, but no study has examined pseudoneglect in schizophrenia at the neural level. We investigated pseudoneglect using the visual P3 event-related potential and the mental number bisection (MNB) task in 21 patients and 25 controls. Using an oddball task, participants were asked to discriminate an infrequent (‘one’ or ‘nine’) from a frequent written number (‘five’). The P3 ERP components were delayed to the targets on the right of the MNL (‘nine’) compared to the targets on the left (‘one’) in controls. The effect of number magnitude on the P3 latency was not observed in the patients. In MNB task, the patients did not show the normal leftward bias observed in healthy individuals. Our findings indicate a lack of pseudoneglect and the presence of an anomalous brain asymmetry in schizophreni

Arrhythmogenic Risk Assessment Following Four-Week Pretreatment With Nicotine and Black Tea in Rat

Background: There is the controversy concerning the main component of tobacco, which is responsible for its arrhythmogenesis. In addition, there is the lack of adequate information about the influence of combination of black tea and nicotine on heart rhythm. Objectives: This study aimed to examine whether pretreatment with black tea and nicotine could modulate the susceptibility to lethal ventricular arrhythmias. Materials and Methods: Animals were randomized to control, black tea, nicotine, and black tea plus nicotine groups. Test groups were treated with black tea brewed (orally) and nicotine (2 mg/kg, subcutaneous), alone and in combination for four weeks. On day 29, aconitine was infused intravenously for induction of cardiac arrhythmia. Results: In comparison with the control group, each of tea and nicotine significantly decreased the duration of the ventricular tachycardia (VT) plus ventricular fibrillation (VF) and the score of arrhythmia severity (P < 0.05 and P < 0.01, respectively,). The latency for the first VT event was significantly longer in the all test groups, but VF latency was significant only in tea and nicotine groups compared with control group (P < 0.05 and P < 0.01, respectively).Threshold dose of aconitine for inducing VT and VF increased in all test groups, but only VT showed a significant difference in comparison to the control group (P < 0.001). Conclusions: The findings suggest that sub-chronic consumption of nicotine or black tea alone with appropriate doses could potentially be antiarrhythmic and its combination regimen does not increase the risk of fatal ventricular arrhythmias during four-week consumption period in rats. Keywords: Ventricular Arrhythmia, Black Tea, Nicotin

Abnormalities of Motor Imagery and Relationship With Depressive Symptoms in Mildly Disabling Relapsing-Remitting Multiple Sclerosis

The effectiveness of motor imagery (MI) as an adjunct to physical rehabilitation has previously been shown. Motor imagery ability can be affected by neurologic disorders that affect motor and cognitive function. This study was designed to assess MI ability in persons with mildly disabling relapsing-remitting multiple sclerosis (RRMS) based on the functional and cognitive dysfunctions. Methods: Twenty-two participants with RRMS and 23 age-, gender-, and education-matched comparison subjects were evaluated by a battery of MI tasks, including a kinesthetic and visual imagery questionnaire, a mental hand rotation task, and a visual guided pointing task. Results: There was no significant difference in MI vividness between the participants with MS and the comparison group, but the accuracy and temporal correspondence of MI in the participants with MS differed significantly from those in the comparison group. Depression scores were significantly higher in participants with MS (P < 0.001), and depression was significantly correlated with disability (r = 0.4; P < 0.05). The correlation between accuracy of MI in the participants with MS and their cognitive ability was significant (r = 0.57; P < 0.05). The MI duration of participants with MS was significantly correlated with their disability (r = 0.59; P < 0.05) and their cognitive ability (r = −0.38; P = 0.009). Discussion: The preservation of MI ability was observed in participants with RRMS; however, abnormalities in accuracy and temporal aspects of MI were observed even in the participants with mild disease. Abnormalities in temporal aspects and accuracy of MI were related to disability and cognitive ability, respectively. In participants with MS, depression should be considered as a confounding factor for the MI task results. Conclusions: Our finding could be considered in the application of MI during the rehabilitation of persons with MS

Single and Repeated Ultra–Rapid Detoxification Prevents Cognitive Impairment in Morphine Addicted Rats: A Privilege for Single Detoxification

Background: Opioids have been shown to affect learning and memory processes. Different protocols of morphine withdrawal can substantially vary in their success to prevent opioid induced impairments of cognitive performance. In the present study, we report the effects of single and repetitive ultra-rapid detoxification (URD) on spatial learning and memory in morphine addicted rats. Methods: Morphine (10 mg/kg) was intraperitoneally (IP) injected in male rats once a day over one week and after which they were detoxified with naloxone administration under anesthesia. For the repetitive procedure, a second one week morphine treatment with a second subsequent detoxification was performed. Control groups received an equivalent volume of saline injections. Spatial learning and memory was evaluated using the Morris water maze (MWM) task. Findings: Both protocols of morphine administration resulted in a severe spatial memory impairment that could be significantly prevented by both single and repetitive URD. However, memory abilities in animals treated with repetitive URD were still significantly lower than in animals of the corresponding control group. Alterations in motor activity or sensory-motor coordination between morphine treated and control animals could be ruled out by comparing swimming speed and visible platform performances that were not different between groups. Thus, URD and, specifically single URD, can prevent the spatial memory impairments in addicted rats. Conclusion: As opioid addiction is an extending and serious concern in many societies, these findings may have clinical values and therapeutic implications for patients who experience multiple opioid relapses

Numerical distance effect in patients with schizophrenia

There is growing evidence showing that mental representation of numbers is impaired in patients with schizophrenia. Yet, no study has examined the distance effect in the patients. We assessed the distance effect using two number size comparison tasks, with different number references (5 and 7) in 23 patients and 28 healthy individuals. Response times and error rates significantly increased when the distances between the centered references and the targets decreased in both groups. However, patients responded significantly slower and had more error rates compared to controls. Our finding indicates distance effect in patients is similar to the controls, indicating an automatic numerical processing is preserved in patients with schizophrenia

Maternal Separation and the Risk of Drug Abuse in Later Life

Maternal separation (MS) is defined as the termination of the continuity of mother-child relationship after the relationship is established. Although MS and maternal deprivation are different in terms of their definitions, these two terms are usually used interchangeably. This review aims to investigate the effect of MS on drug intake in adulthood. It has been proved that animal models are helpful in evaluating the effects of MS on drug intake risk in adulthood. There are relatively acceptable studies in this field on some drugs such as morphine, ethanol, and cocaine. However, very few animal studies, or even no animal study, have been conducted on some other drugs. The majority of these studies have considered MS as a risk factor for drug intake in adulthood. Different mechanisms are proposed for this phenomenon. Brain reward pathways are one of the main exploratory pathways of this process. Despite the importance of the issue, no human study with a specific concentration on investigating the relationship between MS and drug abuse in later life was found. Causal studies are warranted on humans to investigate the effect of MS on drug intake in later life

Is It Time to Review our Educational Program for the Electrocardiography Operators?

No abstract available

Date Fruit Extract Is a Neuroprotective Agent in Diabetic Peripheral Neuropathy in Streptozotocin-Induced Diabetic Rats: A Multimodal Analysis

Background. To study the effects of an aqueous extract of date fruit (Phoenix dactylifera L. Arecaceae) diet on diabetic polyneuropathy (DPN) in streptozotocin- (STZ-) induced diabetic rats. Methods. The effects of a date fruit extract (DFE) diet on diabetic neuropathy in STZ-induced diabetic rats were evaluated and compared with a nondiabetic control group, diabetic control group (sham), and vehicle group with respect to the following parameters: open field behavioral test, motor nerve conduction velocity (MNCV), and morphological observations. Results. In the model of STZ-induced of diabetic neuropathy, chronic treatment for 6 weeks with DFE counteracted the impairment of the explorative activity of the rats in an open field behavioral test and of the conduction velocity of the sciatic nerve (MNCV). In addition, pretreatment with DFE significantly reversed each nerve diameter reduction in diabetic rats. Conclusion. DFE treatment shows efficacy for preventing diabetic deterioration and for improving pathological parameters of diabetic neuropathy in rats, as compared with control groups

Effects of Maternal Separation on Nicotine-Induced Conditioned Place Preference and Later Spatial Learning and Memory Function in Adolescent Male Rats

Background: Disturbances in maternal care have been associated with increased risk for drug abuse later in life. However, there has been little investigation of the effects of maternal separation (MS), a model of early life stress, on nicotine dependence, specifically during adolescence. In the present study, we aimed to investigate the effect of MS on nicotine-conditioned place preference (CPP) in adolescent male rats. We also examined the impact of nicotine on spatial learning and memory impairments induced by MS.Methods: Rat pups were exposed to daily MS for 15 (MS15) or 180 (MS180) minutes during the first 2 weeks of life or reared under normal animal facility rearing (AFR) conditions. In postnatal day (PND) 28-34, they were conditioned with nicotine [0.6 mg/kg, subcutaneously (SC)] or saline and tested for preference over a period of 6 conditioning trials. Morris water maze (MWM) testing was performed to assess spatial cognitive function.Findings: The MS procedure used in our study failed to affect nicotine reward as measured by CPP in the adolescent male rats. Notably, significant spatial learning deficit was seen in the MS180 rats compared to those in the AFR and MS15 groups and nicotine administration modified the MS-induced learning defect in adolescent male rats.Conclusion: In conclusion, although MS revealed no influence on the sensitivity to the nicotine's reinforcing effects in adolescent male rats, the simultaneous effect of MS on learning performance may be altered by nicotine intake